Extraction of protease from Aspergillus tamarii URM 4634 in aqueous two-phase system under continuous and discontinuous process.

Aqueous two-phase systems have been studied for almost a century to separate biomolecules in harmless conditions. Proteases produced by Aspergillus tamarii URM 4634 were extracted in polyethylene glycol (PEG)/phosphate aqueous two-phase system under discontinuous and continuous (perforated rotative discs column) process. On the discontinuous process, it was evaluated the effect of operational conditions (PEG molar mass and its concentration, phosphate concentration and pH) over the partition coefficient, activity yield and purification factor. Protease partitioned to PEG-phase with partition coefficients up to 55.73. The best process parameters were 17.5% of PEG, with molar mass 8000 g·mol-1, 15% of phosphate salt at pH 6, with 113.15% of activity yield and purification factor of 2.62. Under continuous extraction, hold up data showed that 57.1% of the discontinuous phase was available for protein extraction. Further, separation achieved 90.0% of efficiency. The yields surpassed 100% in almost all runs, and the best purification factor was 1.84, with both flows of 2 mL·min-1. Thus, the best operational conditions reached an activity yield of 95.3% and 90.0% of separation efficiency. Hence, aqueous two-phase system PEG/phosphate extraction is an efficient process for separation of proteases produced by Aspergillus tamarii URM 4634, under continuous extraction likewise under discontinuous process.

Genotypic correlation and path analysis in early and super-early maize genotypes.

The aims of this study were to assess the linear relationships between agronomic and nutritional traits and to identify promising traits for indirect selection in early and super-early maturing maize genotypes. Two trials were run in the 2009/2010 agricultural year, each consisting of a randomized block design with three replications. One trial was run on 36 early maturing maize genotypes and the other on 22 super-early maturing genotypes. Six agronomic traits, 11 protein-nutritional traits, and four energetic-nutritional traits were measured. Error normality assumptions were verified using the Kolmogorov-Smirnov test and residual variance homogeneity assumptions using the Levene test. Analysis of variance and the F-test were run for each of the 21 traits. Next, the genotype correlation coefficient matrix was estimated for the 21 traits and each trial. Ridge path analysis was based on values of k = 0.00 and k = 0.10 on the diagonal of X'X correlation matrix, taking the nutritional traits as principal variables and agronomic traits as explanatory variables. The number of days from sowing to male flowering, the number of days from sowing to female flowering, plant height, ear insertion height, ear weight and grain yield can be used in indirect selection as indicators of grain nutritional quality.

Multicollinearity in canonical correlation analysis in maize.

The objective of this study was to evaluate the effects of multicollinearity under two methods of canonical correlation analysis (with and without elimination of variables) in maize (Zea mays L.) crop. Seventy-six maize genotypes were evaluated in three experiments, conducted in a randomized block design with three replications, during the 2009/2010 crop season. Eleven agronomic variables (number of days from sowing until female flowering, number of days from sowing until male flowering, plant height, ear insertion height, ear placement, number of plants, number of ears, ear index, ear weight, grain yield, and one thousand grain weight), 12 protein-nutritional variables (crude protein, lysine, methionine, cysteine, threonine, tryptophan, valine, isoleucine, leucine, phenylalanine, histidine, and arginine), and 6 energetic-nutritional variables (apparent metabolizable energy, apparent metabolizable energy corrected for nitrogen, ether extract, crude fiber, starch, and amylose) were measured. A phenotypic correlation matrix was first generated among the 29 variables for each of the experiments. A multicollinearity diagnosis was later performed within each group of variables using methodologies such as variance inflation factor and condition number. Canonical correlation analysis was then performed, with and without the elimination of variables, among groups of agronomic and protein-nutritional, and agronomic and energetic-nutritional variables. The canonical correlation analysis in the presence of multicollinearity (without elimination of variables) overestimates the variability of canonical coefficients. The elimination of variables is an efficient method to circumvent multicollinearity in canonical correlation analysis.

Laparoscopic incisional hernia repair in an ambulatory surgery-extended recovery centre: a review of 259 consecutive cases.

PURPOSE: The high prevalence of incisional hernias and an average stay of 3-10 days for open procedures have made this pathology both a health problem and an economic issue. A protocol was developed for performing this procedure in an Ambulatory Surgery Center (ASC) with extended recovery. METHODS: From January 2000 to December 2011, data about all laparoscopic incisional hernia repairs were gathered prospectively. The patients' clinical features, hernia type, intraoperative and postoperative complications and reasons for hospital admission are studied. RESULTS: A total of 259 patients have been operated for incisional hernia (185) or recurrent hernioplasty (74) in our ASC. Laparoscopic repair was successful in 254 patients (98.07 %). Conversion to open surgery was necessary in five patients (1.93 %). A total of 50 patients (19.69 %) in whom surgery was completed laparoscopically were discharged the same day of surgery, 179 (70.47 %) at 24 h and 25 (9.84 %) required a stay of over 24 h. Postoperative pain was severe in 10 % of patients, moderate in 40 %, and mild in 50 %. Complications, mostly minor and self-limiting, were observed in 25 patients (9.84 %) during hospital stay. Five major complications that occured were: bile peritonitis, an acute peritonitis, due to an inadvertent intestinal perforation, and one intestinal obstruction by partial detachment of the mesh, an intra-abdominal hematoma and a colo-cutaneous fistula. There were no deaths in the series. The mean follow-up of patients was 29.35 months (range 12-129 months). The recurrence rate was 7.03 % (n = 18). Four trocar-site hernias were detected. CONCLUSIONS: It is essential to create a protocol with selection criteria that take into account the patient, his entourage, the anesthetic-surgical procedure, and a team dedicated to surgical laparoscopic surgery in an ASC with extended recovery to achieve good results in terms of morbidity and patient safety.